Method, apparatus and recording medium for recording digital data stream

ABSTRACT

A recording medium, apparatus and method for recording a digital data stream on the recording medium are discussed. The method according to an embodiment includes recording the digital data stream by dividing the digital data stream into stream objects; recording common information for the stream objects; and recording stream time map information in a stream information file of the recording medium, the stream time map information including a time mapping list having time search information for searching the stream objects.

This application is a Divisional Application of copending applicationSer. No. 09/467,965 filed on Dec. 21, 1999, the entire contents of whichare hereby incorporated by reference. In addition, this applicationclaims the benefit of the Korean Application Nos. 1999-603 filed on Jan.4, 1999, the entire contents of which are hereby incorporated byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method, apparatus and recordingmedium for recording a digital data medium.

2. Description of the Related Art

In a conventional analog television broadcast, video signals aretransmitted over the air or through cables after being AM or FMmodulated. With the recent advance of digital technologies such asdigital image compression or digital modulation/demodulation,standardization for digital television broadcast is in rapid progress.Based upon the Moving Picture Experts Group (MPEG) format, the satelliteand cable broadcast industries are also moving towards digitalbroadcasts.

The digital broadcast offers several advantages that its analogcounterpart cannot provide. For example, the digital broadcast iscapable of providing services with far more improved video/audioquality, transmitting several different programs within a fixedbandwidth, and offering enhanced compatibility with digitalcommunication media or digital storage media.

In the digital broadcast, a plurality of programs encoded based upon theMPEG format are multiplexed into a single transport stream before theyare transmitted. The transmitted transport stream is received by a settop box at the receiver and demultiplexed into the original programs. Ifa program is chosen from among the demultiplexed programs, the chosenprogram is decoded by a decoder in the set top box and original audioand video signals are retrieved. The retrieved audio and video signalscan be presented by an A/V output apparatus such as a TV.

It is also possible to record the received digital broadcast signals ona storage medium instead of directly outputting the received broadcastsignals to A/V output devices. The stored digital broadcast signals canbe edited and retrieved afterwards. For example, a digital data streamreceived by the set top box can be transmitted to a streamer such as adigital video disk (DVD) recording apparatus through communicationinterfaces such as an IEEE-1394 serial bus and stored in the streamer.The stored digital data stream can be edited and transmitted back to theset top box so that the digital audio and video data can be presented.

For recording a received digital broadcast stream on a recording medium,it is necessary to develop schemes to organize the digital data streamon the recording medium and to create management information for rapidaccess to the recorded data stream.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a method, apparatusand recording medium for recording a digital data medium.

To achieve the object and other advantages and in accordance with thepurpose of the invention, a method for recording a digital data streamon a recording medium, as embodied, comprises: recording the digitaldata stream by dividing the digital data stream into stream objects;recording common information for the stream objects; and recordingstream time map information in a stream information file of therecording medium, the stream time map information including a timemapping list having time search information for searching the streamobjects.

In another aspect of the present invention, an apparatus for recording adigital data stream on a recording medium, as embodied, comprises arecording unit to record the digital data stream by dividing the digitaldata stream into stream objects, to record common information for thestream objects, and to record stream time map information in a streaminformation file of the recording medium, the stream time mapinformation including a time mapping list having time search informationfor searching the stream objects.

In another aspect of the present invention, a recording medium forrecording digital data using a digital data recorder, as embodied,comprises: a digital data stream divided into stream objects andrecorded on the recording medium; common information recorded on therecording medium for the stream objects; and stream time map informationrecorded in a stream information file of the recording medium, thestream time map information including a time mapping list having timesearch information for searching the stream objects.

In another aspect of the present invention, a method for recording adigital data stream on a recording medium, as embodied, comprises:recording the digital data stream by dividing the digital data streaminto stream objects; recording a playlist for the stream objects, theplaylist being recorded in a common information file of the recordingmedium; and recording stream time map information in a streaminformation file of the recording medium, the stream time mapinformation including a mapping list having time search information forsearching each of the stream objects.

In another aspect of the present invention, an apparatus for recording adigital data stream on a recording medium, as embodied, comprises arecording unit to record the digital data stream by dividing the digitaldata stream into stream objects, to record a playlist for the streamobjects, the playlist being recorded in a common information file of therecording medium, and to record stream time map information in a streaminformation file of the recording medium, the stream time mapinformation including a mapping list having time search information forsearching the stream objects.

In another aspect of the present invention, a recording medium forrecording digital data using a digital data recorder, as embodied,comprises: a digital data stream divided into stream objects andrecorded on the recording medium; a playlist for the stream objects, theplaylist being recorded in a common information file of the recordingmedium; and stream time map information recorded in a stream informationfile of the recording medium, the stream time map information includinga mapping list having time search information for searching the streamobjects.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention, illustrate preferred embodiments of theinvention, and together with the description, serve to explain theprinciples of the present invention.

In the drawings:

FIG. 1 is a block diagram of an apparatus in which the present inventionmay be advantageously employed;

FIG. 2 is the syntax of the management information created by the methodfor creating search information for recorded digital data streams inaccordance with the present invention;

FIG. 3 is a pictorial representation of the stream time map informationas a part of the management information created by the method forcreating search information for recorded digital data streams inaccordance with the present invention;

FIG. 4 is a pictorial representation for explaining the digital datastream recording operation in accordance with the present invention; and

FIG. 5 is a pictorial representation for explaining the managementinformation created by the method for creating search information forrecorded digital data streams in accordance with the present invention;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In order that the invention may be fully understood, preferredembodiments thereof will now be described with reference to theaccompanying drawings.

FIG. 1 depicts a block diagram of an apparatus in which the presentinvention may be advantageously employed. The apparatus comprises a settop box 100, a communication interface (IEEE-1394), and a streamer 200.

The set top box 100 receives transport streams encoded by systemencoders and broadcast by a plurality of broadcasting stations anddemultiplexes the received transport streams. After a system decoder 120decodes the transport stream of a program tuned by a tuning unit 110, acontrol unit 140 outputs the decoded transport stream to an A/V outputdevice such as a TV set for presentation.

The set top box 100 may transmit a program chosen by a user to thestreamer 200 through the IEEE-1394 interface so that the transmittedprogram is recorded on a recording medium 230 such as a digital videodisk by the streamer 200.

Upon a request by a user, the set top box 100 may receive a programretrieved from the recording medium 230 by the streamer 200 through theIEEE-1394 communication interface so that the received program can bepresented on a TV set after being decoded by the decoder 120.

For carrying out these tasks, the set top box 100 and the streamer 200should be able to access the management information regarding theprograms recorded on the recording medium 230. To this end, informationfiles are used to deal with the recorded data. An applicationinformation file is utilized by the set top box 100 and a streamerinformation file is utilized by the streamer 200. A common informationfile is utilized by both the set top box 100 and the streamer 200. Theseinformation files are recorded on the recording medium 230.

The application information file is retrieved by a stream reproducingunit 240 of the streamer 200 when the set top box 100 is initialized orrequests the file. The retrieved application information is transmittedto the set top box 100 through the IEEE-1394 communication interface andloaded into the management information area M2 of a memory 150 by acontrol unit 140 of the set top box 100. When a new program is recordedor recorded data is edited, the application information loaded in thememory 150 is updated by the control unit 140 to include managementinformation on the newly recorded or edited program. If a user requestsretrieval of a specific program, the control unit 140 requests thestreamer 200 to retrieve the program, with reference to the applicationinformation. When the set top box 100 terminates a recording mode or isshut down, the application information in the memory 150 is transmittedthrough the IEEE-1394 communication interface to the streamer 200 andrecorded on the recording medium 230 by a stream recording unit 220controlled by a control unit 250 of the streamer 200.

The streamer information file and common information file are retrievedby the stream reproducing unit 240 of the streamer 200 when the streamer200 is initialized and loaded into a memory 260 by the control unit 250of the streamer 200. When a new program is recorded or recorded data isedited, the streamer and common information is updated to includemanagement information on the newly recorded or edited program by thecontrol unit 250. If a user requests retrieval of a specific program,the control unit 250, responsive to a request signal from the set topbox 100 retrieves the associated program recorded on the recordingmedium 230 with reference to the streamer and common information loadedin the memory 260. When the set top box 100 terminates a recording modeor is shut down, the streamer and common information in the memory 260are recorded on the recording medium 230 by the stream recording unit220 controlled by the control unit 250.

The syntax of the information files and the structure of recorded datawill be explained with reference to FIG. 2.

As shown in FIG. 2, the application information file (application.IFO)comprises a table of content (TOC) and a service information (SI) table.The table of content (TOC) contains random-access entry points thatallow random access to the recorded data stream and the serviceinformation (SI) table contains the information on the recorded digitalstream. The common information file (common.IFO) contains an originalplaylist automatically created when a digital data stream is recorded,presentation sequence information (Cell) of the recorded data stream,and a user-defined playlist created when a user edits the presentationsequence of the recorded data stream. The table of content and theplaylist are common information for the stream objects (SOBs).

The streamer information file (streamer.IFO) is intended to deal withstream time map general information (STMAP_GI) and a mapping list(MAPL). The stream time map general information (STMAP_GI) is managementinformation regarding stream object units (SOBUs) organized on therecording medium and stream objects (SOBs) each, of which comprises aplurality of stream object units (SOBUs) and the mapping list (MAPL) istime search information regarding the stream object units (SOBUs) andstream objects (SOBs). Each stream object (SOB) has a one-to-onecorrespondence with each Cell contained in the original playlist andeach Cell is contained in the user-defined playlist and has a one-to-onecorrespondence with each stream object (SOB).

The stream time map general information (STMAP_GI), as shown in FIG. 3,comprises several fields representing the stream object unit size(MAPU_SZ), the weight of the LSB of the mapping list entries (MTU_SHFT),index number (INDEX_NO) indicating an arbitrary entry of the mappinglist (MAPL), the number of mapping list entries (MAPL_ENT_Ns), startpacket arrival time (S_SAPAT), and last packet arrival time (S_E_APAT).The mapping list (MAPL) comprises mapping entries (MAPU_ENT), eachmapping entry containing the incremental application packet time(IAPAT).

The method for creating and recording search information for recordeddigital data streams in accordance with an embodiment of the presentinvention will be explained with reference to FIGS. 1, 2, and 3. If auser requests recording of a received digital data stream on therecording medium 230, the control unit 140 of the set top box 100notifies the control unit 250 of the streamer 200 that a recording modehas been set and begins to transmit the received digital data stream tothe streamer 200 through the IEEE-1394 interface. Concurrently, thecontrol unit 140 of the set top box 100 records the entry pointinformation that allows random access to the transport stream packets ofthe digital data stream in the application information (application.IFO)loaded in the management information area (M2) of the memory 150 orrecords the entry point information in the common information(common.IFO) as a part of the playlist. Also, the control unit 140detects the information on the data stream currently being recorded fromthe program service information (SI) loaded in the program informationarea (M1) of the memory 150 and records the service information in theservice information (SI) table of the application information(application.IFO).

The control unit 250 of the streamer 200 controls the stream recordingunit 220 so that the data stream received through the IEEE-1394communication interface is recorded on the recording medium 230. Thedata stream is organized in sectors on the recording medium 230 and apredetermined number of sectors constitute a stream object unit (SOBU).The process is repeated until the recording mode terminates, therebycreating a stream object (SOB) which is a group of data streams recordedby a single recording operation.

The control unit 250 of the streamer 200 creates presentation sequenceinformation (Cell) regarding the created stream object (SOB) and recordsthe Cell in the Cell layer of the common information (common.IFO) aspresentation sequence information corresponding to the record (RCD) ofthe original playlist. For searching for stream object units (SOBUs)constituting the stream object (SOB), the time length of every streamobject unit (SOBU) is sequentially recorded in the mapping list (MAPL).To be more specific, a count value counted at a constant time intervalwhile a stream object unit (SOBU) is created, namely, the incrementalapplication packet time (IAPAT) is recorded in the mapping entry field(MAPU_ENT) corresponding to the associated stream object unit (SOBU), asshown in FIGS. 4 and 5. In addition, the sum of a predetermined numberof incremental application packet times IAPATs (the numbersparenthesized in FIG. 5) is calculated and the sum is recorded as acoarse mapping entry (C_MAP_ENT) which is coarse search timeinformation.

The index number (INDEX_NO) of the first mapping entry (MAPU_ENT) of themapping list (MAPL) or the first coarse mapping entry (C_MAP_ENT)associated with the stream object (SOB) is recorded in the stream timemap general information (STMAP_GI). In FIG. 5, the index number K of thefirst mapping entry related to the stream object SOB #n is recorded asidentification information for indexing the location of the streamobject SOB #n.

If a user requests retrieval of a certain interval of a data streamrecorded on the recording medium, for example recorded datacorresponding to the time interval from 10 minutes to 20 minutes, thecontrol unit 150 of the streamer 200 first searches Cells for a Cell(Cell 2 in FIG. 2) having a recording time corresponding to the starttime 10 minutes. Then, the control unit 150 detects the index numberpointing to the start position of the stream object SOB 2 correspondingto the chosen Cell 2 from the stream time map general information(STMAP_GI). Subsequently, the control unit 150 begins to detect theincremental application packet times (IAPATs), starting from the mappingentry pointed to by the index number. By summing the detectedincremental application packet times (IAPATs) and multiplying the sumvalue by the unit time of each count, the start position of the streamobject unit (SOBU) corresponding to the requested search time 10 minutescan be found. Finally, data retrieval begins from the transport streampacket whose packet arrival time coincides with the requested time.

If a user requests retrieval of the recorded data corresponding to thetime interval from 40 minutes to 60 minutes and the Cell having arecording time corresponding to the requested time 40 minutes is Cell 3,the control unit 150 detects the index number pointing to the startposition of the stream object SOB 3 corresponding to the chosen Cell 3from the stream time map general information (STMAP_GI). Subsequently,the control unit 150 begins to detect the incremental application packettimes (IAPATs) listed in the mapping list MAPL 3. By summing thedetected incremental application packet times (IAPATs) and multiplyingthe sum value by the unit time of each count, the start position of thestream object unit (SOBU) corresponding to the requested time 40 minutescan be found. Finally, data retrieval begins from the transport streampacket whose packet arrival time coincides with the requested time.

The method for creating and recording search information for recordeddigital data streams of the present invention enables rapid and precisesearch of a specific interval of the recorded digital data, providedthat the digital data streams are recorded on a recording medium asgroups of stream objects.

The invention may be embodied in other specific forms without departingfrom the sprit or essential characteristics thereof. The presentembodiments are therefore to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription and all changes which come within the meaning and range ofequivalency of the claims are therefore intended to be embraced therein.

1-24. (canceled)
 25. A method for recording a digital data stream on arecording medium, comprising: recording the digital data stream bydividing the digital data stream into stream objects; recording aplaylist for the stream objects, the playlist being recorded in a commoninformation file of the recording medium; and recording stream time mapinformation in a stream information file of the recording medium, thestream time map information including a mapping list having time searchinformation for searching each of the stream objects.
 26. The method ofclaim 25, wherein each of the stream objects has a plurality of streamobject units, and the mapping list has the time search information forsearching each of the stream object units.
 27. The method of claim 25,wherein the mapping list includes a plurality of sub mapping lists, eachof the sub mapping lists has the time search information for searchingthe corresponding one of the stream objects.
 28. The method of claim 25,further comprising recording a table of content in an applicationinformation file of the recording medium.
 29. The method of claim 28,wherein the table of content includes random-access entry pointinformation that allows random access to the recorded data stream. 30.The method of claim 25, further comprising recording presentationsequence information of the recorded digital data stream in the commoninformation file.
 31. The method of claim 25, wherein the step ofrecording the playlist further includes recording random-access entrypoint information that allows random access to the recorded data streamas a part of the playlist.
 32. An apparatus for recording a digital datastream on a recording medium, comprising: a recording unit to record thedigital data stream by dividing the digital data stream into streamobjects, to record a playlist for the stream objects, the playlist beingrecorded in a common information file of the recording medium, and torecord stream time map information in a stream information file of therecording medium, the stream time map information including a mappinglist having time search information for searching the stream objects.33. The apparatus of claim 32, wherein each of the stream objects has aplurality of stream object units, and the mapping list has the timesearch information for searching each of the stream object units. 34.The apparatus of claim 32, wherein the mapping list includes a pluralityof sub mapping lists, each of the sub mapping lists has the time searchinformation for searching the corresponding one of the stream objects.35. The apparatus of claim 32, wherein the recording unit records atable of content in an application information file of the recordingmedium.
 36. The apparatus of claim 35, wherein the table of contentincludes random-access entry point information that allows random accessto the recorded data stream.
 37. The apparatus of claim 32, wherein therecording unit records presentation sequence information of the recordeddigital data stream in the common information file.
 38. The apparatus ofclaim 32, wherein the recording unit for recording the playlist recordsrandom-access entry point information that allows random access to therecorded data stream as a part of the playlist.
 39. A recording mediumfor recording digital data using a digital data recorder, comprising: adigital data stream divided into stream objects and recorded on therecording medium; a playlist for the stream objects, the playlist beingrecorded in a common information file of the recording medium; andstream time map information recorded in a stream information file of therecording medium, the stream time map information including a mappinglist having time search information for searching the stream objects.40. The recording medium of claim 39, wherein each of the stream objectshas a plurality of stream object units, and the mapping list has thetime search information for searching each of the stream object units.41. The recording medium of claim 39, wherein the mapping list includesa plurality of sub mapping lists, each of the sub mapping lists has thetime search information for searching the corresponding one of thestream objects.
 42. The recording medium of claim 39, further comprisinga table of content recorded in an application information file of therecording medium.
 43. The recording medium of claim 42, wherein thetable of content includes random-access entry point information thatallows random access to the recorded data stream.
 44. The recordingmedium of claim 39, further comprising presentation sequence informationof the recorded digital data stream recorded in the common informationfile of the recording medium.
 45. The recording medium of claim 39,wherein the playlist includes random-access entry point information thatallows random access to the recorded data stream.